In JCTVC-P1005_v1, Strong Intra Smoothing (SIS) is allowed to apply to chroma when chroma format is 4:4:4. When intra_smoothing_disabled_flag is equal to 0 and either cldx is equal to 0 or ChromaArrayType is equal to 3, the filtering process of neighboring samples specified is invoked with the sample array p and the transform block size nTbS as inputs, and the output is reassigned to the sample array p. In RExt6.0 SIS is only allowed for luma. Thus, there is a mismatch on how to deal with SIS for the chroma in 444 chroma format.